Low Frequency Expansion And Performance Evaluation Of Wide Dip Angle Geophones

Seismic exploration is the main means of oil and gas resources exploration,and the geophone is located at the front end of the geophone acquisition system to receive seismic signals,whose performance directly affects the quality of seismic data.Only by improving the low frequency response of the geophone can the deep low frequency seismic signal be received,and only wide inclination geophones can adapt to the more complex geomorphology.The traditional geophone has poor low-frequency response and small working inclination,which seriously restricts the development of seismic exploration technology.In response to the above problems,this paper designs a zero-pole electronic compensation network to improve the low-frequency response characteristics of the wide inclination geophone SGO-15 with a natural frequency of 15 Hz,and improves the pickup capability of low-frequency signals.The sensitivity test and noise level test were conducted for the uncompensated and compensated SGO-15 detector system respectively to verify the correct sensitivity model and noise model.The experimental tests proved that the critical damping second-order compensation circuit extended the natural frequency of the SGO-15 from 15 Hz to 1Hz and increased the sensitivity of the low frequency band by 38 d B.The experimental results show that the modified SGO-15 can still maintain good amplitude and frequency characteristics under wide inclination,so the modified SGO-15 can be used for exploration of deep oil and gas resources in complex landscapes such as deserts and mountains.The paper also designed and developed a system test and evaluation scheme including new geophone sensitivity,noise level and other parameters,and formed a system test method,which can be generalized to the comprehensive performance evaluation of geophone.